Background Art
The present invention relates particularly to breathing assistance systems and more particularly to the type of breathing assistance systems found in surgical operating rooms, and similar medical applications.
In the use of such systems, particularly with patients who are experiencing breathing difficulty because of trauma, surgical procedures, or for other reasons, it is generally desirable to provide heated and humidified air to the patient to prevent "drying out" of the mucocilliary tissue of the respiratory system, and reduce patient heat loss caused by evaporation of water vapor from the lungs.
Heretofore, complicated, hazardous and expensive apparatus has been required to condition the air supplied to the patient. Where such a system is in use for a surgical procedure, or other operating room technique, anesthesia gases or other conditioning is often provided for the breathing gas stream. Also, in many applications, it is particularly useful and economical for the air to be recirculated. However, recirculation requires the removal of carbon dioxide from the gas exhaled by the patient.
Such prior art systems for warming and humidifying patient gases require the use of water reservoirs, humidifiers, and complicated delivery systems including complex electrical/electronic controls. Those systems further require complicated hose connections, and knowledge of the control systems; they may require a significant amount of space in the operating room. Setup of these prior art systems is complicated, and the prior art systems require substantial capital outlay as well as costly supplies.
In such previous applications the use of heaters and humidifiers is prevalent in order to provide proper conditioning for the gases supplied to the patient.
No prior art arrangement is known which recognizes that by proper utilization of the heat typically generated by the reaction of carbon dioxide with a granular absorbent material, and proper insulation, the typical expensive and often troublesome heated humidifier, water supply, reservoir, hose connection system, electronic monitoring and control, bulky mounting apparatus, and generally complicated arrangements required by the prior art can be much simplified or eliminated.
No prior art teaching recognizes that such a device can also be isolated from an associated anesthesia machine to prevent cross contamination between patients. The device is further required to warm, humidify and filter the air stream returning to the patient.